The present invention relates to concrete vibrators in general and, in particular, to an attachment for converting a conventional power tool to a concrete vibrator.
For years, concrete vibrating equipment has been used to create vibration in concrete casting, in order to get homogeneous strength and compaction, as well as to avoid creation of air pockets in the concrete. Until the present day, a dedicated device, which is useful only as a concrete vibrator, has been used. This is due, inter alia, to the fact that a very powerful motor is required.
Conventional vibrators include a vibrating poker connected to a flexible shaft. The vibrating poker is introduced into the concrete and, by the power of the turning motor, it creates vibration throughout the concrete. The poker is usually of the eccenter type or pendulum type. The shaft is generally composed of an outer layer with a flexible cable inside, which transmits power from the motor to the poker. The eccenter type and the pendulum type of vibrator require different motors, as the required rate of rotation differs. Many such vibrators are known in the art.
The connection between the flexible shaft and the motor can be of different types, depending upon the maker of the vibrator and the particular powering unit utilized. The powering units are generally either diesel/gasoline motors, or electric motors.
The electric motors used in concrete vibrators are usually of about 2000 W and either take electricity from the mains line, or from portable generators. They have a suitable connection to the flexible shaft to which the poker is attached.
The fuel engines generally include an adapter mounted on the shaft, the adapter being suitable for connecting the flexible shaft to which the poker is attached.
One example of a pendulum type vibrator is described in U.S. Pat. No. 6,065,859 to Breeding. This vibrator is a portable, hand-held concrete vibrating system employing a pendulous vibrator driven by a high speed, two-cycle motor that operates up to speeds of between 5000 and 6000 rpm. A pivoted weight generally coaxially disposed within the head forcibly causes vibrations in response to internal impacts.
Another example is the portable four cycle backpack pendulous vibrator disclosed in U.S. Pat. No. 5,716,131 to Breeding. The backpack includes a rigid frame mounting a four cycle motor that is connected to the vibrator by a flex-shaft and isolated therefrom by an in-line compensator.
An example of an eccentric vibrator is shown in U.S. Pat. No. 4,057,222. This patent describes an immersion vibrator of the type employed for consolidating poured concrete and employing an unbalanced rotor, characterized by a gerotor type motor, operated by hydraulic pressure, for rotating the rotor.
There are several disadvantages in requiring use of a dedicated concrete vibrator. First, these devices are relatively expensive to manufacture and maintain. Second, if they are not readily available on site when the concrete arrives, work cannot proceed until the vibrator arrives. Third, they add to the quantity of equipment which must be carried from site to site.
Accordingly, there is a long felt need for a device which is convertible to a concrete vibrator or which can be used as a power supply for a concrete vibrator, and it would be very desirable to have such a device which is readily available on building sites.
According to the present invention, there is provided an adapter for coupling to a power tool having a motor with about 2000 W power, the adapter including a transmission for coupling the motor of the power tool to a poker, so as to convert the power tool to the power supply for a concrete vibrator.
According to one embodiment of the invention, the transmission includes at least two gear wheels coupleable to a chuck or shaft of the motor of the power tool and, via a flexible shaft, to the poker.
There is also provided a method for making a concrete vibrator, the method including mounting an adapter on a power tool having a motor with about 2000 W power, and coupling the adapter to a poker, thereby converting the power tool to a concrete vibrator.